As shown in FIG. 1, in a conventional orthodontic treatment process, after part of the maxilla (or mandible) 10 is cut off or a tooth 12 is pulled out (usually not the incisor), the tooth 12 or the maxilla (or mandible) 10 is pulled and dragged by an orthodontic archwire 13 after the operation for helping the maxilla (or mandible) 10 to heal over or correcting the position of the tooth 12. In order to maintain the position of the orthodontic archwire 13 relative to the tooth 12, it is usually to apply several orthodontic brackets 14 adhered onto the tooth 12, and each orthodontic bracket 14 is arranged with slot 141 for providing an accommodation for the orthodontic archwire 13. The width and the depth of the slot 141 must be slightly larger than the diameter of the orthodontic archwire 13 such that, not only may the orthodontic archwire 13 be appropriately glided along the extensive direction of the slot 141, but also may the orthodontic archwire 13 be kept from being dropped out of the slot 141.
As known in the prior arts, in order to provide a pulling-and-dragging force to the orthodontic archwire 13, a screw 20 is screwed on a maxilla (or mandible) 10 at the adjacency of a molar 121, then a spring 15 or rubber band is further connected between the screw 20 and the end of the orthodontic archwire 13 for providing an appropriate pulling-and-dragging force. Since the end of this kind of spring 15 used specially for orthodontic treatment in current market is all arranged with a hook ring 151 so, for the connection between the spring 15 and the end of the orthodontic archwire 13, the end of the orthodontic archwire 13 just may be bent into a hook structure 131, then it can be easy to fit the hook ring 151 of the spring 15 into the hook structure 131 of the end of the orthodontic archwire 13, such that both connection is completed. Relatively, the connection between the spring 15 and the screw 20 is more difficult relatively.
U.S. Pat. No. 4,988,292 discloses an abutment for orthodontic anchorage to a dental implant fixture. It comprises an endosseous implant fixture which is fixed in the lower jaw at the site of a missing molar for supporting an abutment for orthodontic anchorage. The abutment and the fixture are connected by a bolt in a detachable manner. However, the abutment of U.S. Pat. No. 4,988,292 does not provide the function of spring hooking. Even if someone tries to hook the spring on the abutment, the spring will be prone to impinge the gingival as previously illustrated. In addition, the fixture is prone to loose since it has identical outer threads and identical outer diameter throughout the entire fixture.
U.S. Pat. No. 5,836,768 discloses a fastening device for fixing orthodontic apparatuses on a dental implant. It comprises an implant which is fixed in the jaw bone, an anchoring screw screwed within an axially arranged threaded bore in the implant, and an occlusal screw located inside the threaded bore and engaged with the anchoring screw. None part of the occlusal screw nor anchoring screw is exposed outside the implant, such that they cannot be used for spring hooking. Even if the spring can be tied (not hook) on a bracket of U.S. Pat. No. 5,836,768, the spring will be prone to impinge the gingival. In addition, the implant is prone to loose since it has identical outer threads and identical outer diameter.
U.S. Pat. No. 5,921,774 discloses a supporting body for use in orthodontic appliance. It comprises a supporting body to be fixed in the jaw bone, an abutment formed with an arm at a side surface thereof, and a male screw for screwing and fixing the abutment onto the top of the supporting body. Since the screw is an independent element and is screwed from a top side of the abutment, therefore the arm can only be form at the side surface of the abutment, and thus the application and flexibility thereof are limited. In addition, the device disclosed by U.S. Pat. No. 5,921,774 comprises at least three elements (e.g., supporting body, abutment and male screw). Not only the cost to manufacture is higher, but also is more complex to use. Moreover, the supporting body is prone to loose since it has identical outer threads (or no threads at all) and identical outer diameter throughout the entire supporting body.
Other prior art, such like U.S. Pat. No. 6,241,516, U.S. Pat. No. 5,071,345, and US Pub. No. 2002/0127510. None of them has been disclosed a screw device which comprises a screw-body part, a platform part and a head part which is detachable from and exposed outside the platform part (or screw-body part) and is operatable to hook the spring for orthodontic treatment.
As known from above description, the prior arts that are used for orthodontic treatment currently still have many shortcomings to be further improved urgently.
Publication No. US 2003/00224315 A1 and Publication No. US 2003/0023182 A1 are two patent applications filed by the same inventor of the present invention, which disclosed some embodiments of improved screw devices for facilitating orthodontic treatments.